Hydrofoil skis



P. F. RIEFFLE May 11, 1965 HYDROFOIL SKIS 2 Sheets-Sheet 1 Filed NOV. 30, 1962 INVENTOR Paul F. Rieffle P. F. RIEFFLE May 11, 1965 HYDROFOIL SKIS 2 Sheets-Sheet 2 Filed Nov. 30, 1962 INVENTOR Paul F. Rieffle United States Patent 3,182,341 HYDROFOIL SKIS Paul F. Rieliie, 234 Institute St., Pittsburgh 10, Pa. Filed Nov. 30, 1962, Ser. No. 241,259 Claims. (1. 9310) This invention relates to hydrofoil skis and particularly to a water ski having spaced hydrofoil structures adapted thereto for the purpose of elevating the ski and rider above the surface of the Water over which they are towed.

Present Water skiing equipment has been heretofore produced only as a means of support for the rider on the surface of the water, very much as snow skis support the weight of the rider on the surface of snow. Water skiing as it is known today has become a popular water sport and those who have participated over the years are now losing their interest because of the limited events that are possible on the skis now available. When using a conventional pair of skis the rider has the option of being towed on the water behind the towboat or going up a ramp at high speed to make a jump over the water. This latter means of making a jump is quite dangerous as it is much like skiing into a wall should the skier fall while trying to negotiate the ramp. The single ski was introduced and called the slalom ski, again being limited to conventional towing on the water or by the skill of the rider caused to define a zig-zag on the water. Other variations of water surface riding means have been suggested such as discs, short shoe skis and the banana ski, all used to enable the rider to turn or spin around. Some have even resorted to water skiing using no support means except their bare feet. It is thus clear that new devices for water skiing have been long sought.

I provide a new and dilferent type of water ski which will increase the thrill of riding water skis, challenge the skill of the rider and add to the present forms of water skiing a new type of water sport enjoyment.

I provide a'support member in the form of a ski for the rider, means for assisting the rider to maintain his balance, and elevating means to elevate the support member and rider above the surface of the water while being towed. I also preferably provide an adjustable means on the elevating means whereby the rider can control the support means to maneuver as conventional water ski, as a flying ski, a jumping ski and a porpoising ski.

The elevating means for elevating the ski and rider are hydrofoils which are detachable should the skier desire to use the same ski in a conventional manner. These hydrofoils are simply wings which can be a plane, either flat or curved and adapted to operate in water. They develop lift just as do the wings of aircraft. The function of the hydrofoils is to lift the vehicle, in this case the ski and rider, clear of the water enabling said ski and rider to travel faster with the same power as would be required to maintain the rider on the water surface when using conventional skis. From the foregoing it becomes evident that, because hydrofoils are more efficient as a lifting means than the ski alone and have less drag, a lesser source of power would be required to maintain the rider above the surface of the water than when the conventional ski is used. The hydrofoils are adjustable relative to the ski to allow for proper trimming with reference to angle of attack or incidence in the water. This permits the rider to compensate for the riders weight and predetermine the planing attitude of the ski. The means of towing the ski and rider differs in that the ski is towed directly by the towboat and not by placing the strain of towing on the rider, also the rider is assisted by a line affixed to the nose of the ski to maintain his balance on the ski along with the usual foot securing means. The ski is controlled by the skier by the shifting of the center of gravity on the skis. Shift- 3,l$2,34l Patented May 11, 1965 "ice ing the riders weight that is leaning left or right for turning, forward or back for porpoising or jumping enables the rider to select direction as well as action of the ski.

In the foregoing general statement I have set out certain purposes, objects and advantages of my invention. Other purposes, objects and advantages will be evident from the following description and the accompanying drawings in which,

FIGURE 1 is a perspective showing of a preferred embodiment of slalom type ski;

FIGURE 2 is a side elevational view of the embodiment sohwn in FIGURE 1;

FIGURE 3 is a top plan view of the embodiment shown in FIGURE 2;

FIGURE 4 is a transverse cross-sectional view taken ahead of the main hydrofoil on the line IVIV of FIG- URE 2;

FIGURE 5 is a transverse cross-sectional view taken ahead of the secondary hydrofoil on the line VV of FIGURE 2; I

FIGURE 6 is a partial enlarged detail view of a hydrofoil joint;

FIGURE 7 is a perspective showing of a second embodiment of my invention;

FIGURE 8 is a top plan view of the embodiment shown in FIGURE 7; 7

FIGURE 9 is a transverse section taken ahead of the main hydrofoil on the line IX-IX of FIGURE 8; and

FIGURE 10 is a transverse section taken ahead of the secondary hydrofoil on the line XX of FIGURE 8.

Referring to the drawings, and particularly to FIG- URES 1-6, I have illustrated a support member 10 in the form of a slalom ski having a foot securing means 11 in which the rider of the ski places one of his feet. The rider inserts the toe portion of his remaining foot in the securing means 12. An eyebolt 13 is fastened at the front of the support member 10 and has anchored thereto two balance support lines 14. At the opposite end of the support lines 14 a handlebar 15 is suitably fastened such as by having the lines 14 pass through holes in the bar 15 and knotted or tied.

In the embodiment illustrated I have shown a pair of front hydrofoils indicated generally at 16 having a pair of support struts 17. The upper edge of the struts 17 are fastened by bolts 19 to a mounting member 18. The member 18 is fastened to the support member 10 as indicated on the drawings by bolts 18a. A towing eye 20 is secured to the underside of the mounting member 18 by screws 21.

Referring to FIGURES 1, 3, 4 and 6 I provide a relatively horizontal foil section 22 and an adjacent integral upwardly sloping foil section 24. The foil sections 22 and 24 join one another along the opposite sides of the strut 17 to form an obtuse angle of approximately The strut 17 bisects this angle as shown in FIGURE 6 and has fixed at its lower end a joint reinforcing plate 25 welded at 26 thereto. The foil sections 22 and 24 are secured to the joint reinforcing plate 25 by epoxy cement and screws 27. Each of the foils has a section bounded "by a flat bottom surface and an upper rounded surface ,suchas is defined between a chord and circumference of a circle. The above description pertains to one-half of the front hydrofoil section designated generally as 16 and is duplicated for the opposite side of the ski, that is, there is a left and right front hydrofoil section 16. As a reinforcing means between the two front hydrofoil sections 16, I provide a brace 23 suitably fastened with screws 23a to the underside of the horizontal foil sections 22 and recessed therein. The purpose of the brace 23 is to assist in rigidity. Preferably the inner end 22a of the horizontal section 22 is sloped upwardly and outwardly to form a dihedral with the bottom surface of the section jumpingc- The towboat will carry the skier through an arc 22. The ends of the angularly upwardly extending sections 24, are formed so that they provide outer end surfaces lying in a plane vertical to the plane of the spaced portions as shown in FIGURES 4 and 6.

Referring to FIGURES 1, 2 3 and 5 I provide a rear hydrofoil section designated generally as 28 on the drawings and having a foil section 2800f a relatively planar configurationwhose upper surface is convex and lower surface fiat. Preferably the bottom surface is provided with a slight dihedral angle and the ends 28b are sloped upwardly and outwardly to form a dihedral with the bottom surface. The foil section 28a isaffixed to a strut 29 having at its lower end a plate 30 welded thereto. The plate 30 is recessed in the lower surface of the .foil section 28a and fastened thereto in a similar manner as previously described for the plate 25 of the hydrofoil section 16. The upper edge of strut 29 is pivotally fas tened by bolt 34 between two mounting members 33 and is pivotally adjustable relative to the said angle members on bolt 34.- After making the necessary adjustments of the rear hydrofoil section 28 a locking bolt 35 is tightened holding the adjustment from any changes while in use. The mounting members 33 are fastened to the trailing end of the support member by bolts 36.

Assuming that the rider of the disclosed invention inserts his left foot in the securing means 11 and his right foot in the securing means 12 and that a towline 40 has been secured to the tow eye and fastened to the towboat, acceleration of the towboat will cause the ski to rise in the water much the same as a conventional ski. The lines 14 and bar 15, forminga stabilizing yoke are used to assist in maintaining the balance of the rider. The rider has only to shift his weight back slightly on his right foot thus changing the center of gravity rearwardly; the ski will rise or become foilborne. The hydrofoils will ride just below the surface of the water thus giving a smoother ride than if the ski were permitted to ride over the rough surface of the water and also providing alower drag. The power requirements to maintain this elevated position on the foils willbe much less, thereforeif thetowboat maintains its power output, there will be a definite increase in the speed of the skier and the boat traversing over the water, Assuming now that the skier wishes to porpoise the .ski causinga rising and falling of the ski, he has only to shift his weight forward on his left footcausing the skito dive, thus bringing the support member 10 to the surface of the water and then by shifting his weight back to the right foot, causing it to rise. It is evident that by rocking forward and-back he will cause the ski also to rise and drop. remains forward on his left foot, the ski support member 10 will stay on the surface. of the water in a conventional'rnanner and having suflicient power in the towboat to accelerate the rider, the rider has only to make an abrupt shift of weight to his-right remand the ski will elevate at a rapid rate, break the surface tension of the waterand become airborne thus creating a means of in the air until he drops back to the water. The skill of the rider, the. power and rate of acceleration of thewtow- 7 ing means will determine the distance of the jump.

In FIGURES 7 through 10 I haveillustrated my invention as applied to a pair of waterskis. In these figures i like members will be the same, identifying numbers with the addition of the prime sign.

In this second embodiment I attach a pair of skis 10' same manner as FIGURE 1; The mounting plate 18' is provided with a tow eye 20' to take the towline from a boat;

If the skier 7 A rear hydrofoil section 28a is fixed to'strut 29'which 10/31 .Brimhall 9 310' 2,081,868 5/37 Hampden 114.66.5 H 2,751,612. 6/ 56. Shepard 114-,66.5X 2,815,518 12/57 Kuehn- 11466.5 X 2,821,948 2/58 -'Harks'on 114-665 X 2,841,805. .7/58 Roudebush 9-310 2,931,332 4/60 Hebrank 114-66.5;X 2,950,923 8/60' 'Forney 9-310 'X 3,121,890 2/64 Rumsey 9-310 0 FERGUS S. MIDDLETON, Primary Examinen is adjustably mounted between mounting members 33 on a second mounting plate 44 which extends between the rear ends of skis 10'. This arrangement will enable those not sufficiently experienced or capable of handling a single ski, but who are sufficiently proficient on a pair of skis, to use the hydrofoil riding means. Balance will, of course, be much easier to maintain on the two-ski form of this invention.

In this particular form it is possible to execute turns by shifting the weight from one skito the other causing the weighted foil section to submerse and the sections to bank similar to the maneuver executed by aircraft when making a turn.

While I have shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied within the scope of the following claims.

I claim: 7

1. A water sports device comprising a water ski, means intermediate the ends of said ski receiving the foot of a user, a hydrofoil member depending from the s'ki intermediate the foot receiving means and the, forward end of said ski, said hydrofoil having two spaced portions generally parallel to the plane of the ski and an angularly upwardly extending portion extending from the outer end of each of said generally parallel portions, said portions parallel to the plane of the ski having inner end surfaces forming a dihedral angle with the bottom of said surfaces, a second hydrofoil adjacent the rearward end of said ski, and tow receiving means on the ski adjacent the forward end. V

2. A water sports device as claimed in claim 1 wherein the outer endsof the angularly upwardly extending, portion are provided with outer end surfaces lying in 'a plane vertical to the plane of the spaced portions.

3. A water sports device as claimed in claim 1 wherein the second hydrofoil has two bottom plane surfaces forming a dihedral angle'therebetween;

4. A water sports device as claimed in claim 1 wherein a stabilizing yoke isjfixed to the forward end of said ski whereby the rider may hold himself in upright position.

5 A'water sports device comprisinga water ski, means intermediate the ends of said ski receiving theffoot of a user, a first hydrofoil member depending from the ski intermediate the foot receiving means and the forward.

hydrofoil adjacent the rearward end of said ski; adjusting means between the ski and said second hydrofoil whereby said second hydrofoil may be adjustably positioned to vary the angle of attack of the foil surface with respect to the ski surface, andtowreceivihg means on. the ski adjacent the forward end.

References Cited by the Examiner UNITED STATES PATENTS MILTON' B UCHLER, Examiner. 

1. A WATER SPORTS DEVICE COMPRISING A WATER SKI, MEANS INTERMEDIATE THE ENDS OF SAID SKI RECEIVING THE FOOT OF A USER, A HYDROFOIL MEMBER DEPENDING FROM THE SKI INTERMEDIATE THE FOOT RECEIVING MEANS AND THE FORWARD END OF SAID SKI, SAID HYDROFOIL HAVING TWO SPACED PORTIONS GENERALLY PARALLEL TO THE PLANE OF THE SKI AND AN ANGULARLY UPWARDLY EXTENDING PORTION EXTENDING FROM THE OUTER END OF EACH OF SAID GENERALLY PARALLEL PORTIONS, SAID PORTIONS PARALLEL TO THE PLANE OF THE SKI HAVING INNER END SURFACES FORMING A DIHEDRAL ANGLE WITH THE BOTTOM OF SAID SURFACES, A SECOND HYDROFOIL ADJACENT THE REARWARD END OF SAID SKI, AND TOW RECEIVING MEANS ON THE SKI ADJACENT THE FORWARD END. 